Maybe that's not what it means for you, but that might be exactly what it means for Sony. Competition is real.
Sony closed Evolution, and they do not own Insomniac (a studio that made some of their biggest franchises ever), they don't own Bluepoint (@ people suggesting they should buy Bluepoint, what big games has Bluepoint made that are actually new IPs instead of remakes? I wouldn't mind Sony having having a studio dedicated to remasters since Bluepoint is really amazing at that, Bloodborne pls), they don't own Kojima Productions, they don't own Quantic Dream, and they don't own Ready At Dawn.
Kojima Productions is an acquisition that sounds like it makes sense considering Kojima's relationship with Sony, but I don't think he wants to be acquired by anyone either.
Of course Sony has Naughty Dog, Santa Monica Studio, Guerrilla, Sucker Punch, Bend, and some others, but considering how long games development takes these days, and also considering the genre those studios specialize in, for Sony, those might not be enough, and they might be looking to expand their horizons.
I would love it if Sony could have their own genre-defining FPS, a crazy arcade racer, and also if they took fighting games more seriously. They'll need new studios for this especially since Guerrilla seems to be done with the FPS genre. Maybe they've noticed that the FPS genre has been suffering though. Bethesda has published some amazing SP FPS like Prey and Wolfenstein and they seem to underperform despite their amazing quality and multiplatform status.
And for those you suggesting that Sony doesn't need to buy anyone else because they could just hire that team for an exclusive and remain independent, you can say that about every single one of the studios Microsoft acquired recently, just like Sony got Ninja Theory to make Heavenly Sword for them and Sony didn't buy them, but Microsoft ended up buying them.